What makes a generic domain so valuable?

I've decided to put in writing a brief summary of information on why generic domains are so valuable, since the sales prices of top tiers seem to still mystify most people.
 
Memorability. Probably the most important element is memorability - when the domain is easily remembered, it increases the initial response rate of any advertising (offline or online) campaign. 
 
Return Visits. A top tier domain also increases return visits, because the brand/domain is so easily remembered. When the brand is easily recalled for subsequent visits, the domain in fact increases the efficiency of any advertising campaign, which ultimately reduces advertising costs in contrast to competitors.
 
Search engine relevance. When a domain exactly matches the keyword for a search term used at a search engine, search ranking for the website improves. In other words, Google is likely to rank a website higher in search results when the domain matches the keyword search term exactly. 
 
Increased click through rate. Additionally, upon viewing a list of search results, a higher precentage of searchers will in fact click on the link of a domain brand that matches the search term of their particular interest. Someone searching for a 'widget' is more likely to click on a search result which shows a link to 'widget.com' than say widgetstoreinc.com.
 
Authoritative. Generic domains, in particular those which represent the industry category itself, such as Cars.com for the auto industry, are automatically assumed to be the authoritative site for information about that industry, product, or subject. 
 
Direct navigation search traffic. A significant number of people, rather than using a search engine to find information about cars, will simply type in cars.com in their browser looking for information about cars.